A crumbling hospital from the 1850s on Roosevelt Island.

World's first "penitentiary," meant to be humane, drove men insane.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

A psychedelic labyrinth on the San Francisco bay.

An exquisite tunnel of cascading flowers.

World's largest collection of serial killer artwork and other macabre exhibits.

A terrific purveyor of natural history objects and curios.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

A colorful street named for the legendary Australian rock band.

The abandoned remains of a once popular zoo, and the grave of the last known Tasmanian Tiger.

The largest shot tower in Australia is a unique reminder of industrial ammunitions history.

This once-booming gold mining hub was basically abandoned overnight.

The ruins of a once prosperous power station have become a mouldering seaside gem.

A town whose main resource was blue asbestos... what could possibly go wrong?

This abandoned railroad tunnel is now home to a micro-colony of bats and a ghost train.

A local landmark that has become a hub of graffiti and urban exploration.

A collaboration of art and ornithology mourns the calls of Sydney's lost birds.

An abandoned jewel of a ballroom on the top floor of Australia’s busiest rail station echoes with the sounds of a bygone era.

The labyrinthine storm tunnels beneath the city of Melbourne are ruled by a band of urban explorers.

A castle hand-built by a Spanish dreamer in the Australian tropical jungle.

A massive stairway that almost wasn't leads to one of Australia's most scenic vistas.